The prior art discloses driving an electrical direct-current load, such as a direct-current machine or an inverter for driving an alternating-current machine by means of a driver circuit which has a rectifier and a voltage transformer for converting an AC mains voltage into any DC voltage. Step-up converters, step-down converters or step-up/step-down converters are typically used as DC-DC converters. The rectifier converts the AC mains voltage into a pulsating DC voltage, a capacitor having a high capacitance typically being connected between the voltage transformer and the rectifier for smoothing the pulsating AC voltage. The DC-DC converter is typically connected on the output side to a smoothing capacitor having a high capacitance in order to provide a constant or nearly constant output voltage.
Depending on the connected electrical load or depending on a rotational speed and a load torque of a connected electrical machine, a corresponding load current arises at the output, and electrical power is accordingly withdrawn by the electrical load of the driver circuit.
It is disadvantageous that electrical energy is exchanged with the intermediate-circuit capacitor, thus reducing the efficiency of the drive circuit. Furthermore, it is disadvantageous that the intermediate-circuit capacitors which are used require a large amount of space and have a high weight.